1. Field of the Invention
The present invention relates to anti-vibration zoom lens optics suitable for single-lens reflex cameras that use photographic film or charge-coupled device.
2. Description of Related Art Including Information Disclosed Under 37 CFR §§1.97 and 1.98
Some state-of-the-art inventions include zoom lenses with a zoom ratio as high as 4×, as set forth below.
Such zoom lenses are featured as having five groups of lens elements arranged in a sequence of positive, negative, positive, positive and negative in refractive power, or as having six groups of lenses arranged in a sequence of positive, negative, positive, negative, positive and negative, which respectively have their second lens groups displaced to compensate for vibration (see Patent Document 1 listed below).
Some other prior art zoom lenses are of 4.1 zoom ratio with five groups of lens elements arranged in a sequence of positive, negative, negative, positive and negative in refractive power, which have their respective fourth lens groups displaced for anti-vibration compensation (see Patent Document 2).
Another type of the prior art zoom lenses are of 3.5 zoom ratio with three groups of lens elements of positive, negative, and positive refractive power arranged in this order, which have their respective third lens groups displaced for anti-vibration compensation (see Patent Document 3).